Conventionally, handy scanners, which are hand-held type scanners, are well known as devices to read symbols marked on products or packing boxes. Among the handy scanners, there is an imaging type handy scanner by which the light emitted from a light source such as LED, etc. is irradiated to symbols such as a two-dimensional code, etc., and the reflecting light is received by an imaging element such as CCD, etc. so as to read the symbols based on the image data.
Further, in the handy scanner, the technology which improves the reading performance of the symbols by irradiating diffused illumination with high uniformity from the reading port of the handy scanner by using a diffusion plate is well known. For example, in Patent Document 1 (JP 2011-60101), as shown in FIG. 29, an optical information reader 1001 emits marker lights MK1, MK3 formed by diffusion light from the first marker light irradiation part 1050a and the second marker light irradiation part 1050c. With this technology, as shown in FIG. 30, a plurality of light sources (light sources 1022a to 1022m) is arranged annularly in order to irradiate regular illumination which is different from the diffused illumination.
On the other hand, the technology which improves the reading performance for reading the symbols by polarizing the light from the light source in a polarized optical system and irradiating the polarized illumination to the symbols is well known.
For example, as shown in FIG. 31, Patent Document 2 (JP 2011-170536) discloses a handy type code reader 2002 in which the light emitted from the light source 2004 is polarized in the first polarizer 2003 and irradiates to the imaging object, and the reflecting light from the imaging object is polarized in the second polarizer 2005.